Digital-to-analog (D/A) converters are key elements in both electronic and photonic signal processing and data transmission. In many optical transmission systems, digital data has to be converted to analog form for processing and/or transmission. Indeed, there are many advantages for using optical technology to implementing D/A converters, for example, high-speed clocking and signal sampling, wide-bandwidth, light-weight components and the like. Additionally, a high-speed arbitrary analog waveform generator can be implemented using a very high-speed D/A converter.
One such optical D/A converter is described in an article entitle “Digital-to-Analog Conversion Using Electrooptic Modulators”, authored by A. Yacoubian et al., IEEE Photonics Technology Letters, Vol. 15, No. 1, January 2003, pages 117–119. However, the disclosed implementation is limited to a so-called 2-bit photonic D/A converter.